148CHAPTER 11: CONFIGURING SPANNING TREE
■Root Guard — Indicates if the interface is acting as the root port of the switch. The possible field values are:
■Enable — Indicates Root Guard is enabled on the port
■Disable — Indicates Root Guard is disabled on the port.
■Port State — Displays the current STP state of a port. If enabled, the port state determines what action is taken on traffic. Possible port states are:
■Disable — Indicates that STP is currently disabled on the port. The port forwards traffic while learning MAC addresses.
■Blocking — Indicates that the port is currently blocked and cannot forward traffic or learn MAC addresses. Blocking is displayed when Classic STP is enabled.
■Listening — Indicates that the port is in Listening mode. The port cannot forward traffic nor can it learn MAC addresses.
■Learning — Indicates that the port is in Learning mode. The port cannot forward traffic, however it can learn new MAC addresses.
■Forwarding — Indicates that the port is in Forwarding mode. The port can forward traffic and learn new MAC addresses.
■Discarding — Indicates that the port is in Discarding mode. The port is listening to BPDUs, and discards any other frames it receives.
■Port Role — Displays the port role assigned by the STP algorithm to provide to STP paths. The possible field values are:
■Root — Provides the lowest cost path to forward packets to the root switch.
■Designated — The port or LAG through which the designated switch is attached to the LAN.
■Alternate — Provides an alternate path to the root switch from the root interface.
■Backup — Provides a backup path to the designated port path toward the Spanning Tree leaves. Backup ports occur only when two ports are connected in a loop by a
■Disabled — The port is not participating in the Spanning Tree.
■Speed — Indicates the speed at which the port is operating.
